Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Using single quantum dots to probe nanowires: Lighting up plasmonic wires with nanometer accuracy

 (a) This is an optical image of the microfluidic crossed-channel device. Flow in the center control region (dashed circle) is manipulated in two dimensions by 4 external electrodes (not shown). Scale bar is 500 μm. (b) This is a schematic of the positioning and imaging technique. A single QD is driven along a trajectory close to the wire by flow control. The inset shows a microcope image of a typical nanowire with 1 μm scale bar.

Credit: JQI
(a) This is an optical image of the microfluidic crossed-channel device. Flow in the center control region (dashed circle) is manipulated in two dimensions by 4 external electrodes (not shown). Scale bar is 500 μm. (b) This is a schematic of the positioning and imaging technique. A single QD is driven along a trajectory close to the wire by flow control. The inset shows a microcope image of a typical nanowire with 1 μm scale bar.

Credit: JQI

Abstract:
Modern telecommunications happens because of fast electrons and fast photons. Can it get better? Can Moore's law---the doubling of computing power ever 18 months or so---be sustained? Can the compactness (nm-scale components) of electronics be combined with the speed of photonics? Well, one such hybrid approach is being explored at the Joint Quantum Institute (*), where scientists bring together three marvelous physics research fields: microfluidics, quantum dots, and plasmonics to probe and study optical nanostructures with spatial accuracy as fine as 12 nm.

Using single quantum dots to probe nanowires: Lighting up plasmonic wires with nanometer accuracy

College Park, MD | Posted on February 5th, 2013

PLASMONICS

When light strikes a strip of metal an electron wave can be excited in the surface. Is this "surface plasmon" a bit of light or electricity. Well, it's a bit of both. The wavelength of this electromagnetic wave is shorter and the energy density higher than that of the incoming laser light; the plasmon is thus tightly localized light constrained to propagate along the meal surface. The science of "plasmonics" has arisen to capitalize on various imaging, sensing, and processing abilities inherent in plasmons. To start with, though, one needs to know exactly what happens at that laser-excited metallic surface. That light is converted into the plasmonic wave; later the energy can be reconverted into light.

Here's where the JQI experiment comes in. The main result of the work, published February 5 in the journal Nature Communications, is to provide a map showing how the metal strip, in this case a silver wire 4 microns long and 100 nm wide, lights up.

MICROFLUIDICS AND QUANTUM DOTS

The other two chief components of the experiment, in addition to plasmonics, are microfluidics and quantum dots. Microfluidics, a relatively new science all by itself, features the movement of nanoliter volumes of fluids through channels defined on microchips, analogous to the conducting paths strung across microprocessors for carrying electrical currents. Quantum dots, nanometer-sized semiconductor balls, are tailored to possess a specified set of allowed energy states; in effect the dots are artificial atoms that can be moved around. In the JQI experiment the 10-nm-wide dots (the important cadmium-selenide layer is only 3 nm thick) float in a fluid whose flow can be controlled by varying an applied voltage. The dots are drawn up close to the nanowire as if they were mines next to a submarine.

Indeed the dot is there precisely to excite the wire. The dot is fluorescence machine---in a loose sense a nanoscopic lightbulb. Striking it with green laser light, it quickly re-emits red light (one photon at a time), and it is this radiation which excites waves in the nearby wire, which acts like an antenna. But the interaction is a two-way street; the dot's emissions will vary depending on where along the length of the wire it is; the end of the wire (like any pointy lightning rod on a barn) is where electrical fields are highest and this attracts the most emission from the dot.

A CCD camera captures light coming from the dots and from the wire. The camera qualities, the optical properties of the dot, the careful positioning of the dot, and the shape and purity of the nanowire combine to provide an image of the electric field intensity of the nanowire with 12-nm accuracy. The intensity map shows that the input red light from the quantum dot (wavelength of 620 nm) has effectively been transformed into a plasmonic wavelength of 320 nm.

Chad Ropp is a graduate student working on the project and the lead author on the paper. "Plasmonic maps have been resolved before, but the quantum mechanical interactions with a single emitter have not, and not with this degree of accuracy," said Ropp.

POSSIBLE APPLICATIONS

In an actual device, the quantum dot could be replaced by a bio-particle which could be identified through the nanowire's observed effect on particle's emissions. Or the dot-wire duo could be combined in various configurations as plasmonic equivalents of electronic circuit components. Other uses for this kind of nanowire setup might exploit the high energy density in the plasmonic state to support nonlinear effects. This could enable the nanowire-dot combination to operate as an optical transistor.

"Nanoscale imaging and spontaneous emission control with a single nano-positioned quantum dot," Chad Ropp, Zachary Cummins, Sanghee Nah, John T. Fourkas, Benjamin Shapiro, Edo Waks, Nature Communications, paper published online 5 February 2013. Chad Ropp, , 301-405-5010

####

About Joint Quantum Institute
The Joint Quantum Institute is operated jointly by the National Institute of Standards and Technology in Gaithersburg, MD and the University of Maryland in College Park.

For more information, please click here

Contacts:
Phillip F. Schewe

301-405-0989

Copyright © Joint Quantum Institute

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

'Exotic' material is like a switch when super thin April 18th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Laboratories

Scientists Capture Ultrafast Snapshots of Light-Driven Superconductivity: X-rays reveal how rapidly vanishing 'charge stripes' may be behind laser-induced high-temperature superconductivity April 16th, 2014

'Life Redesigned: The Emergence of Synthetic Biology' Lecture at Brookhaven Lab on Wednesday, April 30: Biomedical Engineer James Collins to Speak for BSA Distinguished Lecture Series April 16th, 2014

Relieving electric vehicle range anxiety with improved batteries: Lithium-sulfur batteries last longer with nanomaterial-packed cathode April 16th, 2014

Energy Research Facility Construction Project at Brookhaven Lab Wins U.S. Energy Secretary's Achievement Award April 16th, 2014

Microfluidics/Nanofluidics

A*STAR's Simtech collaboration agreements to accelerate the growth and development of the microfluidics industry April 1st, 2014

Dolomite releases novel droplet-on-demand sequencing and droplet generation microfluidic system April 1st, 2014

Heat-Based Technique Offers New Way to Measure Microscopic Particles March 13th, 2014

New partnership between Malvern Instruments and RheoSense brings m-VROCi to industrial markets February 28th, 2014

Govt.-Legislation/Regulation/Funding/Policy

'Exotic' material is like a switch when super thin April 18th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Novel stapled peptide nanoparticle combination prevents RSV infection, study finds April 17th, 2014

INSCX™ exchange to present Exchange trade reporting mechanism for engineered nanomaterials (NMs) to UK regulation agencies, insurers and upstream/downstream users April 17th, 2014

Chip Technology

'Exotic' material is like a switch when super thin April 18th, 2014

Scientists open door to better solar cells, superconductors and hard-drives: Research enhances understanding of materials interfaces April 14th, 2014

Obducat has launched a new generation of SINDRE® Nano Imprint production system April 11th, 2014

Scientists in Singapore develop novel ultra-fast electrical circuits using light-generated tunneling currents April 10th, 2014

Optical Computing

Scientists in Singapore develop novel ultra-fast electrical circuits using light-generated tunneling currents April 10th, 2014

Nanosheets and nanowires April 1st, 2014

Unavoidable disorder used to build nanolaser March 25th, 2014

A mathematical equation that explains the behavior of nanofoams March 22nd, 2014

Discoveries

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

'Exotic' material is like a switch when super thin April 18th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Announcements

Iranian Researchers Present New Model to Strengthen Superconductivity at Higher Temperatures April 19th, 2014

Iranian Researchers Produce New Anti-Cancer Drug from Turmeric April 19th, 2014

'Exotic' material is like a switch when super thin April 18th, 2014

Innovative strategy to facilitate organ repair April 18th, 2014

Quantum Dots/Rods

Shiny quantum dots brighten future of solar cells: Photovoltaic solar-panel windows could be next for your house April 14th, 2014

Nanotech Business Review 2013-2014 April 9th, 2014

'Quantum Dots Market by Product (QD Displays, Lasers, Medical Devices, Solar Cells, Chip, Sensor), Application (Healthcare, Optoelectronics, Sustainable Energy), Material (Cadmium Selenide, Sulfide, Telluride), and Geography - Forecast & Analysis (2013 - 2020)' March 31st, 2014

Quantum Dots Take Center Stage at Inaugural Event: QD Vision Co-Founder and CTO Dr. Seth Coe-Sullivan to Chair First Quantum Dots Forum, March 26, 2014, San Diego, CA March 25th, 2014

Photonics/Optics/Lasers

High-temperature plasmonics eyed for solar, computer innovation April 17th, 2014

Scientists Capture Ultrafast Snapshots of Light-Driven Superconductivity: X-rays reveal how rapidly vanishing 'charge stripes' may be behind laser-induced high-temperature superconductivity April 16th, 2014

Lumerical files a provisional patent that extends the standard eigenmode expansion propagation technique to better address waveguide component design. Lumerical’s EME propagation tool will address a wide set of waveguide applications in silicon photonics and integrated optics April 16th, 2014

Near-field Nanophotonics Workshop in Boston April 14th, 2014

Alliances/Partnerships/Distributorships

Virus structure inspires novel understanding of onion-like carbon nanoparticles April 10th, 2014

Peer Reviewed and Approved for Science by the the Washington Academy of Sciences April 3rd, 2014

New JEOL-Nikon MiXcroscopy Correlative Imaging Solution March 27th, 2014

Quantum Dots Take Center Stage at Inaugural Event: QD Vision Co-Founder and CTO Dr. Seth Coe-Sullivan to Chair First Quantum Dots Forum, March 26, 2014, San Diego, CA March 25th, 2014

Research partnerships

Novel stapled peptide nanoparticle combination prevents RSV infection, study finds April 17th, 2014

Scientists Capture Ultrafast Snapshots of Light-Driven Superconductivity: X-rays reveal how rapidly vanishing 'charge stripes' may be behind laser-induced high-temperature superconductivity April 16th, 2014

Scalable CVD process for making 2-D molybdenum diselenide: Rice, NTU scientists unveil CVD production for coveted 2-D semiconductor April 8th, 2014

Carbon nanotubes grow in combustion flames April 1st, 2014

NanoNews-Digest
The latest news from around the world, FREE







  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE